The present invention relates to a stackable plastic container and especially suitable for transporting hazardous liquids manufactured as one piece in a blow molding process. The container has the form of a parallelepiped with rounded corners and edges and is provided with a handle at its top portion. Within the top portion, in the vicinity of the front wall, the container is also provided with a filling and pouring socket. A U-shaped stacking surface protrudes from the top portion and surrounds the handle. It has a planar contact surface for receiving further identical containers to be stacked thereon. The U-shaped stacking surface is comprised of two parallel legs and a stacking shoulder which is arranged opposite the filling and pouring socket.
Such containers must fulfill the government regulations for the transport of hazardous materials by railway, highways or sea, such as the code on hazardous material for transportation by railways, highways, sea for Germany. Corresponding international laws exist everywhere in the world. The testing methods provided in the code establish very strict requirements concerning the mechanical and chemical stability of such containers, especially after a long-time chemical exposure to hazardous liquids such as peroxides for which the containers are to be certified. The chosen terminology "containers for transporting hazardous liquids" is to be understood such that they fulfill the requirements of the test methods denoted above.
Furthermore, it will be a future requirement for such container that they must be disposed such as to be emptied completely since the respective recycling or reclamation facilities will only accept containers in which no small amounts of liquid contained therein will be retained.
The embodiment of such containers with rounded corners and edges is for example disclosed in European Patent Application 0 235 384 and have the advantage of a great mechanical stability in comparison to containers with right angle edges which are known from European Patent Application 0 266 851. With right angle edges, corrosive rupture resulting from chemical exposure to hazardous filling materials frequently occur. Both types of containers, however, have the disadvantage that stacking caps are required.
In the aforementioned containers and in such containers as disclosed in German Utility Model 87 00 445 and in German Patent Application 32 24 038, the legs of the U-shaped stacking surface of the top portion of the container are shortened in the area of the pouring socket and are sloped downward towards the connection of the pouring socket to the top portion. Accordingly, the front wall which is adjacent to the pouring socket intersects an imaginary horizontal plane through the container at the elevation of the connection of the pouring socket to the top portion. When the aforementioned containers are tilted to the side during the pouring step, which is essentially unavoidable, a small amount of liquid will remain within the lower portions of the container shoulder; the container cannot be emptied completely.
It is therefore an object of the present invention to provide a container which fulfills to the requirements of the transportation code for hazardous materials even under extreme conditions and which may be emptied completely even when tilted sideways which happens almost inevitably during the pouring step.